SELF- AND AIR-BROADENED OXYGEN A-BAND PARAMETERS

Abstract

Self- and air-broadened oxygen A-band spectra, previously reported by Brown and Plymate} were combined with new higher pressure (1 to 3 atm) spectra of air and fitted with a multispectrum analysis to investigate lineshapes and to improve the precision of the molecular parameters for the O$_2$ A-band at 13100 \wn. These data were recorded with the McMath-Pierce Fourier-transform interferometer located at the National Solar Observatory on Kitt Peak in Arizona.\ The transition wavenumbers have been referenced to recent stabilized cavity-ring-down laser measurements of Robichaud et al.} calibrated against a $^{39}$K standard. Deviations from the conventional Voigt profile were observed while better fits were obtained with Dicke-narrowing (Rautian or Galatry) and speed-dependent Voigt linehapes. Line-mixing, apparent in the higher pressure air spectra, was successfully fit through the R-branch head with first-order Rosenkranz coefficients exhibiting odd-even J staggering indicative of interbranch spin-rotation coupling.\ The results will be compared to other literature measurements and theoretical models of the oxygen A-band.}